Sheet gripper for cylinder presses



Nov. 13, 1951 J J [SELLA 2,575,172

SHEET GRIPPER FOR-CYLINDER PRESSES Filed Aug. 4. 1949 2 SHEETS-SHEET l INVENTOR.

JQHN J. ISELLA BY AUSTIN WILHFLM8 CAQL$0N v AA A'H-QRNE vs 1951 J. J. ISELLA SHEET GRIPPEIR FOR CYLINDER PRESSES 2 SHEETSSHEET 2 Filed Aug. 4. 1949 Fig. 4

INVENH/"i= JOHN J. 'ISELLA "1 Mi "W Patented Nov. 13, 1951 SHEET GRIPPER FOR CYLINDER PRESSES John J. Isella, North Haven, Conn., assignor, by mesne assignments, to Heisler Machine and Tool Co., Clifton, N. J., a partnership Application August 4, 1949, Serial No. 108,48;

1 Claim.

This invention relates to improvements in cylinder presses. Cylinder presses are widely used in the paper box industry for printing large sheets of board from which individual box blanks are subsequently cut. Cylinder presses are also used for cutting and scoring or, to use a different term employed in the trade, for cutting and creasing printed sheets.

This invention is equally applicable to the flat bed type of cylinder press in which the sheetpasses between the cylinder and a flat bed as well as to the rotary type of press in which the sheet passes between two cylinders.

In order to attach to a cylinder a sheet which is about to be printed or cut and scored grippers are employed. The most commonly used form of gripper is a finger-like device secured to an oscillating gripper shaft on the cylinder. This shaft is usually mounted in a recess or trough at the periphery of the cylinder and extends generally parallel to the cylinder axis. Mechanism is provided on the press for oscillating this shaft in one direction or the other in order to move the grippers towards the cylinder surface for clamping a sheet thereon, oscillation of the shaft in the opposite direction releasing the sheet.

Conventional grippers generally consist of a yoke or body having an aperture therethrough for mounting of the body on the gripper shaft. A finger integral with the body extends from the body portion and has generally teeth at the end at the point where the finger engages the sheet and urges it against the cylinder surface.

In order to be effective, the gripper finger has to bear down on the sheet with a certain amount of force causing the finger to flex slightly. Breakage of gripper fingers is a frequent occurrence. Such breakage occurs when a gripper is overstressed due to improper adjustment and it also occurs as a result of fatigue of correctly adjusted grippers. Breakage of grippers is a source of great annoyance, since a gripper shaft usually carries 18 to 2G grippers on it nearly all of which must be removed for the replacement of one or a few broken grippers. In so doing it is first necessary to demount the. shaft from the cylinder.

The present invention provides an improved gripper which after its initial installation never requires removal from the gripper shaft, so that it is not necessary to demount the entire gripper shaft for the purpose of replacing damaged grippers. The improved gripper comprises a body and a separate gripper arm which may be secured to the body without removal of the body from the gripper shaft. The gripper requires no adjustment of the body relatively to the gripper shaft if it is necessary to replace a defective arm.

Over and beyond the feature of convenient replacement of defective arms the gripper embodying the present invention offers advantages of adjustment which are not found in grippers in conventional construction. According to conventional practice-grippers of various sizes are supplied for one and the same press and it is necessary to replace a complete set of long grippers, if the particular job requires short grippers. This again involves demounting of the gripper shaft from the machine, a time-consuming operation. The improved gripper embodying the present invention is adiustable so that the length of the arm may be varied.

These and other features and advantages of the invention will appear more fully from the detailed description which follows accompanied by drawings showing, for the purpose of illustration, a preferred embodiment of the invention. The invention also consists in certain new and original features of construction and combination of elements hereinafter set forth and claimed.

Although the characteristic features of this invention which are believed to be novel will be particularly pointed out in the claim appended hereto, the invention itself, its objects and advantages, and the manner in which it may be carried out may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part of it in which:

Figure 1 is a perspective view of a portion of the surface of a press cylinder showing a gripper shaft and two grippers embodying the present invention;

Figure 2 is a section taken on plane 2--2 of Figure 1;

Figure 3 is an elevational side view of the improved gripper;

Figure 4 is an end view of the gripper shown in Figure 3; and

.Figure 5 is a plane view of the gripper shown in Figure 3. I

In the following description and in the claims various details will be identified by specific names for convenience. The names, however, are intended to be as generic in their application as the art will permit. Corresponding reference characters refer to corresponding parts in the several figures of the drawings.

In the drawings accompanying, and forming part of, this specification, certain specific disclosure of the invention is made for the purpose of explanation of broader aspects of the invention, but it is understood that the details may be modified in various respects without departure from the broad principles of the invention and that the invention may be applied to other structures than the ones shown.

The press cylinder ll of which only a small portion is shown in Figure 1 is provided with a trough or a recess l2 through which a gripper shaft 13' extends. The gripper shaft (3 is pivotally mounted in the end walls of the trough, one such mounting being visible at 14. The grippers I5 are mounted on a gripper shaft 13. Each gripper comprises an arm 16 hearing down upon the cylinder surface I! when the gripper shaft is turned in a counter-clock-wise sense. If the shaft 13 is turned in the opposite sense the gripper 7 arm is lifted off the cylinder surface to release a sheet l8 previously held by the gripper.

The mechanism for ioscillating the gripper shaft 13 is conventional and does not form part of this invention. It will therefore be sufiicient to state that the shaft is oscillated periodically in a counter-clock-wise direction for gripping a sheet and in clock-wise direction for releasing it.

Sheets are fed toward the cylinder substantially in the direction in which the sheet 18 is shown in Figure 2. The edge of the sheet comes to rest against a feeder stop [9 immediately prior to being engaged by the grippers and clamped onto the cylinder surface. The stop 19 may then be lifted to increase its clearance from the cylinder surface and be dropped again when the next sheet is fed onto the cylinder.

I The construction of an improved gripper embodying the present invention is shown in detail in Figures 3 to 5.

A body member 20 has a bore or hole 21 therethrough for mounting on the gripper shaft I 3. A set screw 22 extends into a tapped hole in the body and bears against a key 23 for clamping the body 20 to the gripper shaft in a predetermined clock-dial position.

A guideway 24 preferably of prismatic shape is provided in the body 20. The guideway extends at right angles with respect to the axis of the hole 2|. A slot 25 extends into the body 20 from the guideway 24 and separates the top portion of the body into parts 26 and 21 which may be drawn together by socket screws 28 extending into tapped holes 29.

The gripper 16 has a gripper portion 30 at its front end. The gripper portion is preferably serrated for tight frictional engagement with the sheet and its other end is formed as a straight shank portion 31 fitting into the guideway. The shank portion of the illustrated form of gripper is of prismatic cross-section and is easily slidable within the guideway 24 for the purpose of adjustments of the length of the gripper arm. It may be clamped in adjusted position by tightening the socket screws 28, the prismatic shape of the shank providing for particularly secure hold of the arm in clamped position.

It is thus apparent that each of the 18 to 20 grippers normally required for a cylinder may easily be adjusted for proper reach and tension with respect to the sheet on the cylinder surface. An angular adjustment is possible by turning the gripper body with respect to the shaft, and

the length of the gripper arms may be varied by sliding the shank portion 3] of the gripper arm 16 within the guideway whereafter the socket screws 28 are tightened.

It is also apparent that in the event of damage to one of the gripper arms the arm may be replaced with a minimum of effort without disturbing the setting of the gripper body and without removing or disturbing the position or adjustment of the other grippers mounted on the same shaft.

The invention thus provides an improved gripper construction which not only reduces the time of replacement of damaged grippers to a small fraction of the time heretofore required but also provides the added feature of adjustment of the length and gripping angle of the gripper arm thereby obviating the necessity of keeping in stock grippers of difierent lengths for the same press.

Obviously the novel gripper is not limited to use on cylinder presses for handling paper board but may be used with equal advantage on presses handling other sheet material such as sheet metal.

What is claimed is:

A gripper for releasably clamping a sheet of flexible material, such as paperboard, to the surface of the cylinder of a cylinder press of the type equipped with an oscillating gripper shaft on the cylinder extending parallel to the cylinde axis,

the gripper comprising, a body member having a hole therethrough for mounting the body member on the gripper shaft, the body member having a. prismatic straight guideway therein extending substantially at right angles with respect to the axis of said hole; the body having further a slot therein extending from said guideway into the body substantially normal to the axis of said hole; a gripper arm having a curved finger portion with teeth at one end and having at its other end a substantially straight shank portion of prismatic cross-section fitting said prismatic guideway; means on said body member for clamping said body member to the gripper shaft; and a bolt extending through the body member substantially parallel to the axis of said hole for drawing together the two portions of the body member separated by said slot to clamp the shank portion I of the arm in adjusted position.

JOHN J. ISELLA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED' STATES PATENTS Number Name Date 161,049 Megill Mar. 23, 1875 274,546 Ayres Mar. 2'7, 1883 323,168 Lindemeyer July 28, 1885 433,101 Shea July 29, 1890 2,378,523 Worthington June 19, 1945 FOREIGN PATENTS Number Country Date 4,345 Switzerland Dec. 17, 1891 625,624 France Apr. 25, 19 7 314,441 Great Britain June 26, 1929 

